Change And Analysis Of The Activation Energy Derived From Nonisothermal Kinetic Data

Non-isothermal kinetic equation is expressed in the following form: (?)The aim of kinetic studies is to extrapolate three kinetic parameters A , E and f (α). However, the kinetic parameters of the reaction extrapolated by various methods appear ambiguous because the kinetic parameter differs significantly among different methods. The ambiguous central issue for the non-isothermal kinetics is the significance of the activation energy and reaction model.In this paper, assuming that the rate limiting step of solid particles decomposition is step-shaped nuclear and growth, if heating rate is raised ,the new formation nuclei total volume of the molarV is reduction which is certificated by the non-isothermal kinetic basic equation,the relationship of the number of the new formation nuclei and heating rate is found by the homogeneous formation model, the number of the new formation nucle will increase if heating rate is raised.A fuction of the number of the formation nuclei N- N = N [αrmax(β)] is defined, which is related to the conversion fraction corresponding to the maximum reaction rate under different heating rate. The relationship of activation energy of formation nuclei with the conversion, heating rate and N function is expressed as following: (?)The relationship of the activation energy of growth nuclei with the conversion, rate, heating rate and N function is given in the following form(?)The differential activation energy of reaction, E 'a, can be derived by combining Arrhenius differential equation with non-isothermal kinetic equations, which is composed of the differential activation energy of rate, E 'r and the differential activation energy of mode function, E ' f(α), and the equation may be given as following (?)The activation energy of calcium carbonate decomposition is obtained by kinetics data under different heating rates. The results show out as the following:(1)The intrinsic activation energy, Ea 0 is found out when conversion fraction is zero, which represented the inherent dynamics of reactants, as the following form:(?)(2) The intrinsic model is explotrated by Ea 0 has been determined as the following form (?) (3) A fuction of the differential activation energy and conversion is expressed as the following form (?)...